Process for acetylene production



United States Patent 3,392,210 PROCESS FOR ACETYLENE PRODUCTION RobertS. Puistonen, New Canaan, Conn., assignor to Chemical ConstructionCorporation, New York, N.Y., a corporation of Delaware Filed Apr. 1,1965, Ser. No. 444,575 17 Claims. (Cl. 260-679) ABSTRACT OF THEDISCLOSURE An improvement is provided in acetylene processes in whichthe hot acetylene-containing gas stream is quenched with heavy aromaticquench oil. The quench oil accumulates solid carbon particles which areremoved from the gas stream during the quench step, and at least aportion of the quench oil is treated to remove entrained solid carbonparticles. The quench oil portion is mixed with a stream of lighthydrocarbon oil such as benzene, a benzene derivative such as xylene, ora light parafiinic oil such as hexane, which has a low boiling pointrelative to the heavy aromatic quench oil. A homogeneous mixture ofheavy aromatic and light aromatic or parafiinic oils containing solidcarbon particles is produced. This homogeneous mixture is then separatedinto a solid carbon phase free of aromatic oils and an aromatic oraromatic-parafiinic oils mixture free of solid carbon particles byfiltration or centrifuging. The aromatic or aromaticparaflinic oilsmixture is then heated and distilled, to vaporize the light aromatic orparaffinic oil. The residual liquid aromatic oils phase consisting ofheavy aromatic oil is then recycled. The vaporization of light oil fromthe oils mixture is preferably carried out during processing of the mainprocess gas stream to remove residual heavy aromatic oil vapor. The gasstream is scrubbed and refluxed with light aromatic or parafiinic oil,to condense the heavy aromatic oil into a liquid phase with concomitantvaporization of the light aromatic or parafiinic oil into the gasstream. The liquid phase oils mixture produced after separation of solidcarbon particles, and consisting of heavy aromatic oil together withllght aromatic or paraflinic oil, is added to the light aromatic orparafiinic oil during the gas scrubbing and reflux step. The lightaromatic or paraffinic oil component of the oils mixture is vaporizedinto the gas stream, while the heavy aromatic oil component of the oilsmixture combines with the heavy aromatic oil liquid condensed from thegas stream and is subsequently recycled, to the initial gas quench step.

The present invention relates to the production of acetylene, andparticularly relates to the removal of solid carbon particles from thequench oil employed in the production of acetylene. An improved sequenceand method are provided, whereby the solid carbon particles arecompletely separated from the quench oil without loss of quench oil dueto thermal degradation or inclusion in the separated solid carbonparticles.

The production of acetylene generally involves the reaction of a fluidhydrocarbon such as methane or naphtha with oxygen at elevatedtemperature and under partially reducing conditions. Naphtha is a liquidpetroleum distillate fraction containing mostly paraffinic hydrocarbonshaving from to 9 carbon atoms per molecule, and the usual composition ofnaphtha is described in detail in US. patent application Ser. .No.160,749 filed Dec. 20, 1961, now US. Patent No. 3,262,886. The reactionbetween the fluid hydrocarbon and oxygen produces a hot gas streamprincipally containing acetylene, solid carbon particles, carbonmonoxide, hydrogen and water vapor.

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Minor proportions of methane, carbon dioxide, aromatics and nitrogen mayalso be present. The hot gas stream is quenched to prevent furtherreaction with concomitant loss of acetylene, by projecting a liquidstream of heavy aromatic oil principally comprising naphthalene into thehot gas stream. It will be appreciated by those skilled in the art thathomologs of naphthalene may also be efiectively employed as the heavyaromatic quench oil. Thus, in the process description and claims infra,reference to naphthalene will be understood to encompass homologs ofnaphthalene as well as naphthalene itself, although naphthalene is thepreferred heavy aromatic quench oil. A heavy aromatic oil such asnaphthalene is the preferred quench agent, because the heavy aromaticoil is relatively resistant to thermal degradation due to contact withthe hot gas stream, and also because the heavy aromatic oil is veryefiective in wetting and thereby entraining the solid carbon particles,so as to remove a major portion of the carbon particles from the gasstream during quenching. The heavy aromatic oil containing entrainedcarbon particles is separated from the quenched gas stream containingvaporized heavy aromatic oil, and the quenched gas stream is passed tofurther processing for purification and ultimate recovery of productacetylene.

The heavy aromatic quench oil containing entrained solid carbonparticles is then cooled and recycled for further gas quenching. It isapparent that a buildup of solid carbon particles concentration in thequench oil will occur. Thus, it is a usual practice to treat a portionor all of the quench oil stream for removal of entrained solid carbonparticles. In most instances, a minor portion of quench oil stream iswithdrawn from the recycling quench-oil, and is treated to remove solidcarbon particles. The purified portion of quench oil is then added tothe main stream of quench oil, and thus the solid carbon particlescontent of the total recycling quench oil is maintained ata suitable lowlevel.

The solid carbon particles have been removed from the quench oil streamin the prior art by mechanical procedures such as filtration 0rcentrifuging of the quench oil, to attain a solid-liquid separation.This procedure is not totally satisfactory, because of loss of quenchoil which wets and remains with the solid carbon phase, and also becauseof mechanical difiiculties in handling the relatively viscous slurry.Another prior art approach involves heating of the quench oil-carbonmixture, to vaporize and distill off the quench oil, which issubsequently condensed to liquid free of solid carbon particles, andthen recycled. This sequence is also relatively undesirable, because inorder to attain reasonably adequate vaporization and removal of quenchoil from the mass of solid carbon particles, prolonged and intensiveheating must be provided, which results in thermal degradation anddecomposition of a substantial portion of the quench oil.

In the present invention, solid carbon particles are removed from theliquid stream of heavy aromatic quench oil by means of a novel procedureand method sequence. The heavy aromatic oil stream containing entrainedsolid carbon particles is mixed with a stream of light aromatic oilconsisting of benzene or a benzene derivative, such as toluene orxylene, and having a low boiling point relative to the heavy aromaticoil. The median boiling point of the light aromatic oil shouldpreferably be at least 50 C. below that of the heavy aromatic oil.Alternatively, a light paraffinic oil such as hexane or heptane may beemployed instead of the light aromatic oil. Thus, a homogeneous mixtureof heavy aromatic and light aromatic or paraffinic oils containing solidcarbon particles is produced. It has been determined that thishomogeneous mixture is readily separable into a solid carbon phase freeof aromatic oils and an aromatic or aromatic-paraffinic oils mixturefree of solid carbon particles by the use of a conventionalsolids-liquid separation step, such as filtration or centrifuging.Centrifugal separation of the phases has been found to be preferable, inproviding optimum separation without mechanical difiiculties. Thearomatic or aromatic-paraflinic oils mixture is then heated anddistilled, to vaporize the light aromatic or paraflinic oil. Theresidual liquid aromatic oils phase consisting of heavy aromatic oil isthen recycled.

In a preferred embodiment of the present invention, the main process gasstream containing residual heavy aromatic oil vapor is scrubbed andrefluxed with light aromatic or parafiinic oil, to condense the heavyaromatic oil into a liquid phase with concomitant vaporization of thelight aromatic or parafiinic oil into the gas stream. The liquid phasemixture of heavy aromatic oil and light aromatic or paraflinic oilproduced after separation of solid carbon particles is added to thelight aromatic or parafiinic oil during this scrubbing and reflux step,and the light aromatic or paraflinic oil component of the oils mixtureis thus vaporized into the gas stream, while the heavy aromatic oilcomponent of the aromatic oils mixture combines with the heavy aromaticoil liquid condensed from the gas stream.

The principal advantage of the procedure of the present invention isthat solid carbon particles produced during acetylene manufacture areremoved from the heavy aromatic quench oil without loss of quench oildue to thermal degradation or entrainment in the solid carbon particles.The requisite apparatus is simple and operates efficiently on themixture of heavy aromatic oil and light aromatic or paraflinic oil plusentrained solid carbon particles, and the solid carbon is completelyremoved from the liquid phase. In addition, the use of light aromatic orparafiinic oil in a preferred embodiment of the present inventionpermits the removal of solid carbon particles by mixing a light aromaticor paraffinic oil with the heavy aromatic oil-carbon slurry to beintegrated into the sequence for treating and purifying the process gasstream prior to acetylene recovery. Finally, the light aromatic orparaffinic oil component is readily separated from the liquid phasemixture of light aromatic or paraflinic and heavy aromaitc oils bysimple distillation of vaporization, and the uncontaminated heavyaromatic oil is thus readily recycled for further gas quenching withoutloss.

It is an object of the present invention to provide an improvedprocedure for acetylene production.

Another object is to provide an improved method for the removal of solidcarbon particles from the quench oil in acetylene manufacture.

An additional object is to separate solid carbon particles from quenchoil in acetylene manufacture without loss of quench oil.

A further object is to utilize a light aromatic or paraffinic oil in theseparation of solid carbon particles from heavy aromatic quench oilemployed in acetylene production.

Still another object is to integrate and combine the use of lightaromatic or paraflinic oil in the separation of solid carbon particlesfrom heavy aromatic quench oil utilized in acetylene manufacture, withthe treatment of the process gas stream to remove residual heavyaromatic oil vapor.

Still a further object is to separate solid carbon particles from anacetylene-containing process gas stream in an improved manner.

An object is to minimize material handling requirements and simplifyequipment required in the removal of solid carbon particles from thequench oil employed in acetylene manufacture.

These and other objects and advantages of the present invention willbecome evident from the description which follows. In the detailedprocess description infra, reference to light aromatic oil will beunderstood to encompass the alternative usage of a light paraffinic oilsuch as hexane or heptane. Referring to the figure, a flowsheet showingthe process and preferred embodiments of the invention is presented. Thefluid parafiinic hydrocarbon feed stream 1 and oxygen stream 2 arepassed into acetylene burner 3. Stream 1 may consist of any suitablefluid paraffinic hydrocarbon or hydrocarbon mixture, however thehydrocarbon in stream 1 will generally have from one to nine carbonatoms per molecule. As mentioned supra, methane or naphtha are preferredhydrocarbons for use as stream 1, and will usually be employed incommercial installations, although light paraffins such as propane orbutane may also be employed. The mixing of streams 1 and 2 in unit 3takes place in the upper part of unit 3, preferably by means ofinduction of stream 1 into stream 2 via a venturi mixing passage. Theflame reaction of the mixed gas stream takes place at elevatedtemperature and under partially reducing conditions, below perforatedrefractory barrier 4. The resulting hot gas stream in unit 3 willtypically be at a temperature in the range of 1000 C. to 1700 C., andwill usually contain principally from about 5% to 12% acetylene byvolume, together with solid carbon particles, carbon monoxide, hydrogenand water vapor.

The mixed and reacted process gas stream below perforated refractorybarrier 4 is immediately quenched by contact with quench liquid stream 5to a reduced temperature. Stream 5 consists of a liquid stream of heavyaromatic oil principally comprising naphthalene, and Will typically havea median boiling point in the range of 210 C. to 300 C. Stream 5 willalso usually contain entrained solid carbon particles, and wets andentrains additional solid carbon particles by contact with the hot gasstream. The warmed quench liquid is separated from the quenched gasstream in the lower part of unit 3, and collects in the bottom of unit3. Warmed quench liquid stream 6 is withdrawn from the bottom of unit 3,and will usually contain from about 10% to 30% by weight of solid carbonparticles. All of stream 6 may be processed for removal of solid carbonparticles in accordance with the present invention, however stream 6 ispreferably divided into a major portion stream 7 which is recycled forfurther gas quenching and a minor portion stream 8 which is usually lessthan about 5% of stream 6 and is processed for removal of solid-carbonparticles in a man ner to be described infra. Stream 7 is now combinedwith recycle stream 9, derived in a manner to be described infra, andthe combined liquid quench oil stream 10 is passed through Waste heatboiler 11 for cooling and heat recovery via steam generation. The cooledliquid quench oil stream 5 is now recycled for further gas quenching asdescribed supra.

The quenched gas stream, now containing vaporized heavy aromatic oil andresidual solid carbon particles, is withdrawn from unit 3 via stream 12,and is typically at a temperature in the range of C. to 250 C. Stream 12may be processed by a variety of techniques, to remove heavy aromaticoil vapor, residual solid carbon particles and other impurities, priorto recovery of product acetylene. However, in this preferred embodimentof the present invention, stream 12 is passed into the lower part of gasscrubber 13 below gas-liquid contact trays 14. Scrubbing liquid stream15 consisting of a heavy aromatic oil comparable to stream 5 describedsupra, is admitted into the upper part of scrubber 13 above trays 14.Stream 15 differs essentially from stream 5 in composition only in thatthe proportion of entrained solid carbon particles in stream 15 is muchlower than in stream 5. The scrubbing of stream 12 in unit 13 results inthe removal of substantially all of the residual entrained solid carbonparticles from the gas phase into the scrubbing liquid. In addition, thegas stream is cooled in unit 13 and most of the heavy aromatic oil vaporis condensed into the liquid phase.

The resulting warmed heavy aromatic oil scrub liquid is withdrawn fromunit 13 via stream 16, and contains an increment of heavy aromatic oilderived from the quench oil vapor in stream 12 as well as entrainedsolid carbon particles derived from stream 12. Stream 16 is now dividedinto stream 9 which is recycled to the quench step as described supra,and recycle scrub liquid stream 17. The recycle stream 17 is combinedwith recycle heavy aromatic oil stream 18 derived in a manner to bedescribed infra, and the combined liquid heavy aromatic oil stream 19 ispassed through waste heat boiler 20 for cooling and heat recovery viasteam generation. The cooled liquid scrub oil stream 15 is now recycledfor further gas scrubbing and cooling as described supra.

The scrubbed and cooled gas stream now leaves unit 13 via stream 21,which is typically at a temperature in the range of 130 C. to 180 C. andcontains residual heavy aromatic oil vapor together with a very minorproportion of entrained solid carbon particles. Stream 21 is now passedinto the lower part of scrubbing and gas reflux unit 22 below lowerpacked section 23. A final removal of solid carbon particles andcondensation of residual heavy aromatic oil vapor from the gas streaminto a liquid phase is attained in unit 22, together with concomitantvaporization of light aromatic oil into the gas stream, as describedinfra. Thus, the gas stream 21 rises within unit 22 and passes throughpacked section 23, which is any conventional means for gas-liquidcontact such as a packed bed provided with Raschig rings. A scrubbingliquid stream 24 is admitted into unit 22 above bed 23 and is dispersedinto the packing of bed 23, thus flowing downwards and scrubbing therising gas stream. Stream 24 consists of heavy aromatic oil of acomposition similar to stream 5 described supra, and an additionalamount of cool heavy aromatic oil flows downward into packed bed 23 fromgas reflux bubble cap trays section 25 in the upper part of unit 22, tobe described infra. Thus, the rising gas stream is scrubbed and slightlyfurther cooled in bed 23, by cont-act with the downflowing liquid phase.Removal of residual entrained solid carbon particles from the gas streamand condensation of heavy aromatic oil vapor thus takes place in bed 23.The scrub liquid from bed 23 is collected in the bottom of unit 22 andwithdrawn as stream 26. Stream 26 is divided into recycle stream 18which is added to stream 17 as described supra, and stream 27 which isrecycled for further gas scrubbing in bed 23. Stream 27 is combined withmake-up heavy aromatic oil stream 28 to form stream 24. Stream 28 is ofa composition similar to stream 5 described supra, and is added tocompensate for process losses in the system.

The rising gas stream in unit 22 now rises from bed 23 and flows throughgas reflux section 25, which preferably consists of a plurality ofbubble cap traps. A liquid reflux stream 29 is passed into unit 22 abovesection 25. Stream 29 consists of alight aromatic oil such as benzene ora benzene derivative'such as xylene or toluene or a mixture of thesecompounds and usually will have a median boiling point generally in therange of 80 C. to 170 C. Stream 29 preferably consists primarily ofxylene. In any case, the median boiling point of stream 29 is below thatof stream 5 and preferably at least 50 C. lower than that of stream 5.As mentioned supra, stream 29 may alternatively consist of a lightparaflinic oil such as hexane or heptane. Thus, reference to a lightaromatic oil encompasses usage of light parafiinic oil. Stream 29 flowsdownwards through bubble cap plates 25, in reflux contact with therising gas stream, and is substantially completely vaporized into therising gas stream, thus serving to cool the gas stream and condenseresidual heavy aromatic oil vapor to liquid, which flows downward fromsection 25 and into bed 23 as described supra.

A liquid stream 30 consisting of a mixture of light and heavy aromaticoils and derived in a manner to be described infra is preferably alsopassed into unit 22, and onto an intermediate plate 25 having a liquidphase composition comparable to that of stream 30 itself. In essencethen, stream 30 is added to the liquid stream of light aromatic oilduring the scrubbing and. reflux of the gas stream with light aromaticoil. The light aromatic oil component of stream 30 thus is vaporizedinto the rising gas stream, while the heavy aromatic oil component ofstream 30 flows downward through trays 25 in the liquid state and thenceforms a component of the liquid heavy aromatic oil flowing downwardthrough bed 23.

The gas stream is thus further cooled in the reflux section 25, withconcomitant total vaporization of stream 29 into the gas stream andcomplete condensation of heavy aromatic oil vapor from the gas streaminto the liquid phase. The resulting cooled gas stream is withdrawn fromunit 22 via stream 31, typically at a temperature in the range of 70 C.to C., and is now processed to remove light aromatic oil vapor and alsoa major portion of its water vapor content by condensation to the liquidphase. Thus, stream 31 is passed into packed scrubbing tower 32 belowpacked section 33, which is any suitable means for gas-liquid contactsuch as a bed of Raschig rings packing. A liquid stream 34 consisting ofcold scrubbing water is admitted into unit 32 above bed 33, and flowsdownward through bed 33 countercurrent to the rising gas stream, thusserving to condense all of the light aromatic oil vapor and a majorportion of the water vapor from the gas stream into the liquid phase.The resulting cold gas stream, now at a temperature typically in therange of 30 C. to 70 C., is discharged from unit 32 via stream 35, andis passed to suitable processing for the recovery of acetylene in aconventional manner. This procedure, not shown, will typically includecompression of the gas stream 35, followed by scrubbing with a selectiveliquid solvent for acetylene. The liquid solvent containing absorbedacetylene is then heated to evolve a gaseous stream of pure productacetylene.

Returning to unit 32, the water scrub liquid flows downward from packedsection 33 and is withdrawn from the bottom of unit 32 as liquid stream36, which contains separate and immiscible water and organic liquidphases. The organic liquid phase in stream 36 consists of light aromaticoil condensed from stream 31. Stream 36 is now divided into separatestreams of water and light aromatic oil by conventional procedure suchas decanting, thus stream 36 is preferably passed into decanter 37 wherestream 36 divides into separate light aromatic oil layer 38 which flowsover bafile 39, and lower water layer 40. Water is withdrawn from layer40 via stream 41, which is divided into water recycle stream 42 andexcess water stream 43 which is discarded. Stream 43 corresponds to thewater vapor condensed from stream 31 in unit 32. Water recycle stream 42is cooled in cooler 44 and recycled via stream 34 for further gasscrubbing.

The light aromatic oil liquid is withdrawn from decanter 37 as stream45, which is divided into stream 29 and stream 46. Stream 29 is recycledfor gas reflux and cooling as described supra, while stream 46 is nowemployed in the removal of solid carbon particles from the heavyaromatic quench oil. Thus, light aromatic oil stream 46 is now combinedwith heavy aromatic oil stream 8 containing entrained solid carbonparticles in mixer 47, which produces a homogeneous liquid mixture oflight and heavy aromatic oils containing solid carbon particles. Theliquid mixture is discharged from mixer 47 as stream 48, which is nowreadily separable into a solid carbon phase substantially free ofaromatic oils and a liquid aromatic oils mixture substantially free ofsolid carbon in conventional solid-liquid separation means such as afilter apparatus or a centrifugal separator. Centrifugal separation ispreferble in providing more rapid and complete separation in simplerapparatus. Thus, stream 48 is passed into centrifuge 49, whichdischarges a solid carbon phase stream 50 substantially free of aromaticoils and a liquid stream 30 consisting of a mixture of light and heavyaromatic oils substantially free of solid carbon. Stream 30 is nowrecycled to the process as described supra, while stream 50 may bediscarded or utilized as fuel or for other suitable purposes.

Numerous alternatives within the scope of the present invention willoccur to those skilled in the art. In this respect, it is to beunderstood that the process ranges of operating variables, such astemperature ranges enumerated supra, constitute merely a preferredembodiment of the procedure of the present invention and should not beconstrued to modify or restrict the inventive concepts of 10 the presentinvention, since the procedure of the present invention is also operableoutside of these process ranges and may be followed outside of theseprocess ranges in suitable instances.

As mentioned supra, stream 12 may be processed in a 1 ployed as a refluxstream to cool and scrub the quenched gas stream thereby condensingheavy aromatic oil vapor to liquid and producing a gas stream containingvaporized light aromatic oil which is subsequently condensed by coldwater scrub, constitutes a preferred embodiment of the presentinvention. In addition, the process concept in which stream 30,consisting of a mixture of light and heavy aromatic oils, is added tothe liquid light aromatic oil phase on bubble cap tray 25 in unit 22during gas reflux and scrubbing, in order to separate stream intovaporized light aromatic oil component and liquid heavy 30 aromatic oilcomponent which is recycled, constitutes a novel and preferred processsequence and a new combination of process steps within the scope of thepresent in vention.

The alternative of separately heating stream 30 in a special separatedistillation column, to vaporize and separate the light aromatic oilcomponent from aromatic oils mixture 30, leaving a liquid heavy aromaticoil component which is recycled to gas quenching, with subsequentcondensation of the vaporized light aromatic oil component and recycleto mixer 47, would also be employed when stream 12 is processed by meansother than as described supra to recover product acetylene, and lightaromatic oil is not employed for gas scrubbing and reflux.

An example of an industrial application of the present invention willnow be described.

Example A fluid hydrocarbon feed stream 1 consisting of a total of62,040 lbs./ hr. of petroleum naphtha having an average molecular weightof 84 was reacted with a total of 63,700 lbs/hr. of 98% oxygen toproduce an acetylene-containing gas in accordance with the presentinvention. The reaction actually took place in a total of six parallelacetylene burners, with the respective feed streams being divided intosix portions, however flow quantities in the material balance infra willbe expressed as overall totals for the entire facility. The finalproduct gas stream contained 8.82% acetylene by volume, together with35.27% carbon monoxide, 41.14% hydrogen, 3.85% water vapor, 3.98%methane, 3.70% carbon dioxide, and minor proportions of other organicsand inerts. Stream 35 was produced at a temperature of 29.4 C. with atotal production flow rate of 112,890 lbs/hr.

Following is a tabulation of the temperature and flow rate of majorprocess streams in the facility. All flow rates are expressed in lbs/hr.of the individual components present in the flow stream.

In some cases, it may prove relatively less desirable to introducestream 30 into unit 22 for separation into light and heavy aromatic oilphases. This would be especially true when stream 30 contains arelatively high proportion of heavy aromatic oil, because a completeremoval of heavy aromatic oil vapor from the gas stream in trays section25 may then be diflicult to attain. In this case,

stream 30 may be separately heated in a special separate distillationcolumn, to vaporize and separate the light aromatic oil component fromthe aromatic oils mixture 30. The vaporized light aromatic oil componentwould then be separately condensed and directly recycled to mixer 47,and the residual heavy aromatic oil component of stream 30 would berecycled in stream 28 or directly .recycled to quenching as a componentof stream 5. In

this case, stream 45 would be recycled completely as stream 29. Thisalternative would be particularly desirable if the light aromatic oilemployed in mixer 47 for mixing 5 i,'i52','ri66 a 1, 133, 000 35, 890

In the process sequence according to the material balance supra, stream9 was recycled directly into the lower part of unit 3. Hence the flowrates for stream 6 include the added components derived from stream 9.In addition, a small amount of vaporized xylene was present in stream35. This xylene content was recovered during the subsequent processingof stream 35 to recover product acetylene, and was recycled to unit 37.A very minor quantity of residual xylene was present in stream 50 andconstituted a process loss, and a small amount of carbon was present instream 30. However, for all practical purposes,- stream 50 wassubstantially free of naphthalene and xylene, and stream 30 wassubstantially free of carbon. Finally, in actual operation of the processequence, two centrifuges 49 were provided. Stream 46 was divided intotwo equal portions. A first portion of stream 46 was added to stream 8and the mixture was passed to the first centrifuge. The resulting solidscomponent was mixed with the second portion of stream 46 and passed tothe second centrifuge. The resulting solids discharge constituted stream50, while the liquid discharge from the second centrifuge was also addedto stream 8 prior to the first centrifuge.

I claim:

1. In a proces for the production of acetylene wherein a fluidparaflinic hydrocarbon and oxygen are reacted at elevated temperature toproduce a hot gas stream principally containing acetylene, solid carbonparticles, car bon monoxide, hydrogen and Water vapor, said hot gasstreamis quenched to reduced temperature by contact with a first liquidstream of heavy aromatic oil having an elevated boiling point andprincipally comprising naphthalene, said first heavy aromatic oil streamcontaining entrained solid carbon particles is separated from thequenched gas stream containing vaporized heavy aromatic oil and iscooled and recycled for further gas quenching, said quenched gas streamis quenched with a second liquid stream of heavy aromatic oilprincipally comprising naphthalene, whereby said gas stream is cooledand residual entrained carbon and vaporized heavy aromatic oil areremoved from said gas stream, the cooled gas stream is scrubbed andrefluxed with a liquid stream of light aromatic oil selected from thegroup consisting of benzene and benzene derivatives, and having a lowboiling point relative to the boiling point of said heavy aromatic oil,whereby said gas stream is further cooled and residual heavy aromaticoil vapor is condensed from said gas stream, said condensed liquid heavyaromatic oil is recycled for further scrubbing of the quenched gasstream, said light aromatic oil being vaporized into said gas stream,the resulting gas stream containing vaporized light aromatic oil isscrubbed with liquid water whereby said vaporized light aromatic oil andwater vapor are condensed from said gas stream and a liquid streamcontaining a light aromatic oil phase and a separate Water phase isproduced, said condensed light aromatic oil phase is separated from theliquid water phase, the separated liquid tight aromatic oil is recycledfor further gas scrubbing and reflux, and the residual cold gas streamis processed to recover product acetylene, the improved method ofseparating entrained solid carbon particles from said first heavyaromatic oil stream which comprises mixing at least a portion of saidfirst heavy aromatic oil stream containing solid carbon particles with aportion of said separated liquid tight aromatic oil, separating theresulting liquid oils mixture containing solid carbon particles intoasolid carbon phase substantially free of oils and a liquid oils phasesubstantially free of solid carbon, and vaporizing light aromatic oilfrom said liquid oils phase by adding said liquid oils phase comprisinga mixture of light aromatic and heavy aromatic oils substantially freeof solid carbon particles to said gas stream during said scrubbing andreflux of said gas stream with said light aromatic oil, whereby thelight aromatic oil component of said liquid oils phase is vaporized intosaid gas stream and the heavy aromatic oil component of said liquid oilsphase is recovered as a component of the residual heavy aromatic oilliquid condensed from said gas stream. I

2. The process of claim 1, in which said fluid parafiinic hydrocarbonconsists of naphtha.

3. The process of claim 1, in which said fluid paraffinic hydrocarbon ismethane.

4. The process of claim 1, in which said light aromatic oil is xylene.

5. The process of claim 1, in which said liquid oils mixture containingsolid carbon particles is separated into a solid carbon phase and aliquid oils phase by passing said oils mixture through centrifugal meansfor solidliquid separation.

6. A process for the production of acetylene from a hydrocarbon andseparation of solid carbon particles therefrom which comprises reactinga fluid paraflinic hydrocarbon having from one to nine carbon atoms permolecule with oxygen at elevated temperature to produce a hot gas streamprincipally containing acetylene, solid carbon particles, carbonmonoxide, hydrogen and water ture by contact with a liquid stream ofheavy aromatic oil having an elevated boiling point and principallycomprising naphthalene, separating said heavy aromatic oil streamcontaining entrained solid carbon particles from the quenched gas streamcontaining vaporized heavy aromatic oil, dividing said heavy aromaticoil stream containing entrained solid carbon particles into a majorportion and a minor portion, cooling and recycling said major portion ofsaid heavy aromatic oil stream for further gas quenching, cooling andscrubbing said quenched gas stream by contact with a liquid refluxstream comprising a first liquid stream of light aromatic oil, saidfirst light aromaticoil stream comprising a light aromatic oil selectedfrom the group consisting of benzene and benzene derivatives and havinga low boiling point relative to the boiling point of said heavy aromaticoil, whereby heavy aromatic oil vapor and residual entrained carbon areremoved from said quenched gas stream in a liquid heavy aromatic oilcondensate and said first light aromatic oil stream is vaporized intothe cooled gas stream, processing the cooled gas stream to recoveracetylene product, mixing said minor portion of said heavy aromatic oilstream containing entrained solid carbon particles with a second liquidstream comprising a light aromatic oil selected from the groupconsisting of benzene and benzene derivatives and having a low boilingpoint relative to the boiling point of said heavy aromatic oil,separating the resulting aromatic oils mixture containing solid carbonparticles into a solid carbon phase substantially free of aromatic oilsand a liquid oils phase, vaporizing light aromatic oil from said liquidoils phase by adding said liquid oils phase comprising a mixture oflight aromatic and heavy aromatic oils substantially free of solidcarbon particles to said gas stream during said scrubbing and reflux ofsaid gas stream with said light aromatic oil, whereby the light aromaticoil component of said liquid oils phase is vaporized into said gasstream and the heavy aromatic oil component of said liquid oils phase isrecovered as a component of said liquid heavy aromatic oil condensate,and recycling said condensed liquid heavy aromatic oil comprising heavyaromatic oil to said quenching of said hot gas stream.

7. The process of claim 6, in which said light aromatic oil is xylene.

:8. A process for the production of acetylene from a hydrocarbon andseparation of solid carbon particles therefrom which comprises reactinga fluid paraflinic hydrocarbon having from one to nine carbon toms permolecule with oxygen at elevated temperature to produce a hot gas streamprincipally containing acetylene, solid carbon particles, carbonmonoxide, hydrogen and water vapor, quenching said hot gas stream toreduced temperature by contact with a first liquid stream of heavyaromatic oil having an elevated boiling point and principally comprisingnaphthalene, separating said first heavy aromatic oil stream containingentrained solid carbon particles from the quenched gas stream containingvaporized heavy aromatic oil, dividing said first heavy aromatic oilstream containing entrained solid carbon particles into a major portionand a minor portion, cooling and recycling said major portion of saidfirst heavy aromatic oil stream for further gas quenching, scrubbingsaid quenched gas st eam with a second liquid stream of heavy aromaticoil principally comprising naphthalene, whereby said gas stream iscooled and residual entrained carbon and vaporized heavy aromatic oilare removed from said gas stream, further cooling and scrubbing thecooled gas stream to condense and remove residual heavy aromatic oilvapor by contacting said cooled gas stream with a liquid reflux streamcomprising a first liquid stream of light aromatic oil, said first lightaromatic oil stream comprising a light aromatic oil selected from thegroup consisting of benzene and benzene derivatives and having a lowboiling point relative to the boiling point of said heavy aromatic oil,whereby heavy aromatic oil vapor and residual entrained carbon areremoved from said cooled gas stream in a liquid heavy aromatic oilcondensate and said first light aromatic oil stream is vaporized intothe cooled gas stream, processing the cooled gas stream to recoveracetylene product, mixing said minor portion of said first heavyaromatic oil stream containing entrained solid carbon particles with asecond liquid stream comprising a light aromatic oil selected from thegroup consisting of benzene and benzene derivatives and having a lowboiling point relative to the boiling point of said first heavy aromaticoil, separating the resulting aromatic oils mixture containing solidcarbon particles into a solid carbon phase substantially free ofaromatic oils and a liquid oils phase, vaporizing light aromatic oilfrom said liquid oils phase by adding said liquid oils phase comprisinga mixture of heavy and light aroma-tic oils to said cooled gas streamduring said scrubbing and reflux of said gas stream with said firststream of light aromatic oil, whereby the light aromatic oil componentof said liquid oils phase is vaporized into said gas stream and theheavy aromatic oil component of said liquid oils phase is recovered as aliquid component of said liquid heavy aromatic oil condensate, andrecycling said condensed liquid heavy aromatic oil comprising heavyaromatic oil by adding said condensed liquid aromatic oil to said secondheavy aromatic oil stream.

9. A process for the production of acetylene from a hydrocarbon andseparation of solid carbon particles therefrom which comprises reactinga fluid paratfinc hydrocarbon having from one to nine carbon atoms permolecule with oxygen at elevated temperature to produce a hot gas streamprincipally containing acetylene, solid carbon particles, carbonmonoxide, hydrogen and water vapor, quenching said hot gas stream toreduced temperature by contact with a first liquid stream of heavyaromatic oil having an elevated boiling point and principally comprisingnaphthalene, separating said first heavy aromatic oil stream containingentrained solid carbon particles from the quenched gas stream containingvaporized heavy aromatic oil, dividing said first heavy aromatic oilstream containing entrained solid carbon particles into a major portionand a minor portion, cooling and recycling said major portion of saidfirst heavy aromatic oil stream for further gas quenching, scrubbingsaid quenched gas stream with a second liquid stream of heavy aromaticoil principally comprising naphthalene, whereby said gas stream iscooled and residual entrained carbon and vaporized heavy aromatic oilare removed from said gas stream, scrubbing and refluxing the cooled gasstream with a liquid stream of light aromatic oil selected from thegroup consisting of benzene and benzene derivatives and having a lowboiling point relative to the boiling point of said first heavy aromaticoil, whereby said gas stream is further cooled, said light aromatic oilis vaporized into said gas stream, and residual heavy aromatic oil vaporis condensed from said gas stream, recycling said condensed liquid heavyaromatic oil for further scrubbing of the quenched gas stream by addingsaid condensed liquid heavy aromatic oil to said second liquid stream ofheavy aromatic oil, scrubbing the further cooled gas stream containingvaporized light aromatic oil with liquid water, whereby said gas streamis cooled and said vaporized light aromatic oil and water vapor arecondensed from said gas stream into a liquid stream containing a lightaromatic oil phase and a separate water phase, separating said condensedlight aromatic oil phase from the liquid water phase, dividing saidlight aromatic oil phase into a first portion and a second portion,recycling said first portion of said light aromatic oil phase as saidliquid stream of light aromatic oil, processing the residual cold gasstream to recover product acetylene, mixing said second portion of saidlight aromatic oil phase with said minor portion of said first heavyaromatic oil stream containing entrained solid carbon particles,separating the resulting liquid aromatic oils mixture containing solidcarbon particles into a solid carbon phase substantially free ofaromatic oils and a liquid aromatic oils phase substantially free ofsolid carbon, and vaporizing light aromatic oil from said liquidaromatic oils phase by adding said liquid aromatic oils phase to saidgas stream during said scrubbing and reflux of said cooled gas streamwith said liquid stream of light aromatic oil, whereby the lightaromatic oil component of said liquid oils phase is vaporized into saidgas stream and the heavy aromatic oil component of said liquid oilsphase is recovered as a component of said condensed liquid heavyaromatic oil.

10. A process for the production of acetylene from a hydrocarbon andseparation of solid carbon particles therefrom which comprises reactinga fluid paraflinic hydrocarbon having from one to nine carbon atoms permolecule with oxygen to produce a gas stream at a temperature in therange of 1000 C. to 1700 C., said gas stream principally containing fromabout 5% to 12% acetylene by volume together with solid carbonparticles, carbon monoxide, hydrogen and water vapor, quenching said gasstream to a temperature in the range of 180 C. to 250 C. by contact witha first liquid stream of heavy aromatic oil having a median boilingpoint in the range of 210 C. to 300 C. and principally comprisingnaphthalene, separating said first heavy aromatic oil stream containingfrom about 10% to 30% by weight of entrained solid carbon particles fromthe quenched gas stream containing vaporized heavy aromatic oil,dividing said first heavy aromatic oil stream containing entrained solidcarbon particles into a, major portion and a minor portion, said minorportion being less than 5% of the total stream, cooling and recyclingsaid major portion of said first heavy aromatic oil stream for furthergas quenching, scrubbing said quenched gas stream with a second liquidstream of heavy aromatic oil having a median boiling point in the rangeof 210 C. to 300 C. and principally comprising naphthalene, whereby saidgas stream is cooled to a reduced temperature in the range of 130 C. to180 C. and residual entrained carbon and vaporized heavy aromatic oilare removed from said gas stream, scrubbing and refluxing the cooled gasstream with a liquid stream of light aromatic oil selected from thegroup consisting of benzene and benzene derivatives and having a medianboiling point in the range of C. to 170 C., whereby said gas stream isfurther cooled to a temperature in the range of 70 C. to C., said lightaromatic oil is vaporized into said gas stream, and residual heavyaromatic oil vapor is condensed from said gas stream, recycling saidcondensed liquid heavy aromatic oil for further scrubbing of thequenched gas stream by adding said condensed liquid heavy aromatic oilto said second liquid stream of heavy aromatic oil, scrubbing thefurther cooled gas stream containing vaporized lig'ht aromatic oil withliquid water, whereby said gas stream is cooled to a temperature in therange of 30 C. to 70 C., and said vaporized light aromatic oil and watervapor are condensed from said gas stream into a liquid stream containinga light aromatic oil phase and a separate water phase, separating saidcondensed light aromatic oil phase from the liquid water phase, dividingsaid light aromatic oil phase into a first portion and a second portion,recycling said first portion of said light aromatic oil phase as saidliquid stream of light aromatic oil, processing the residual cold gasstream to recover product acetylene, mixing said second portion of saidlight aromatic oil phase with said minor portion of said first heavyaromatic oil stream containing entrained solid carbon particles,separating the resulting liquid aromatic oils mixture containing solidcarbon particles into a solid carbon phase substantially free ofaromatic oils and a liquid aromatic oils phase substantially free ofsolid carbon particles, and vaporizing light aromatic oil from saidliquid aromatic oils phase at a temperature in the range of 70 C. to 130C., by adding said aromatic oils phase to said gas stream during saidscrubbing and reflux of said cooled gas stream with said liquid streamof light aromatic oil, whereby the light aromatic oil component of said13 liquid oils phase is vaporized into said gas stream and the heavyaromatic oil component of said liquid oils phase is recovered as acomponent of said condensed liquid heavy aromatic oil.

11. In a process for the production of acetylene in which a fluidparafiinic hydrocarbon and oxygen are reacted at elevated temperature toproduce a hot gas stream principally containing acetylene, solid carbonparticles, carbon monoxide, hydrogen and water vapor, said hot gasstream is quenched to reduced temperature by contact with a liquidstream of heavy aromatic oil having an elevated boiling point andprincipally comprising naphthalene, said heavy aromatic oil streamcontaining entrained solid carbon particles is separated from thequenched gas stream containing vaporized heavy aromatic oil, theseparated heavy aromatic oil stream is cooled and recycled for furthergas quenching, said gas stream is scrubbed and refluxed in gas-liquidcontact means with a liquid stream of light aromatic oil selected fromthe group consisting of benzene and benzene derivatives, said lightaromatic oil having a low boiling point relative to the boiling point ofsaid gas stream, and the residual cold gas stream is cooled, heavyaromatic oil vapor is condensed from said gas stream, and said lightaromatic oil is vaporized into said gas stream, the condensed liquidheavy aromatic oil is recycled and combined with said separated heavyaromatic oil stream, the resulting gas stream containing vaporized lightaromatic Oil is further cooled to condense liquid light aromatic oil,said condensed liquid light aromatic oil is recycled for furtherscrubbing and refluxing of said gas stream, and the residual cold gasstream is processed to recover product acetylene, the improved method ofseparating solid carbon particles from said heavy aromatic quench oilstream which comprises (a) mixing at least a portion of said heavyaromatic quench oil stream containing solid carbon particles with aportion of said condensed liquid light'aromatic oil,

(b) separating the resulting liquid oils mixture containing solid carbonparticles into a solid carbon phase substantially free of oils and aliquid oils phase substantially free of solid carbon, and

(c) adding said liquid oils phase produced by step (b) into saidgas-liquid contact means during said scrubbing and refluxing of said gasstream, whereby light aromatic oil is vaporized from said liquid oilsphase into said gas stream, and the heavy aromatic q-uench oil componentof said liquid oils phase combines with said condensed liquid heavyaromatic oil and is thereby recycled for further gas quenching.

12. The process of claim 11, in which said light aromatic oil is xylene.

13. The process of claim 11, in which said fluid parafifinic hydrocarbonconsists of naphtha.

14. The process of claim 11, in which said fluid paraffinic hydrocarbonis methane.

-15. The process of claim 8, in which said light aromatic oil is xylene.

16. The process of claim 9, in which said light aromatic oil is xylene.

17. The process of claim 10, in which said light aromatic oil is xylene.

References Cited UNITED STATES PATENTS 3,242,225 3/1966 W. Danz et a1260679 FOREIGN PATENTS 495,789 11/ 1938 Great Britain.

DEL'BERT E. GANTZ, Primary Examiner.

I. D. MYERS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,392,210 July 9, 1968 Robert S. Puistonen It is certified that error appearsin the above identified patent and that said Letters Patent are herebycorrected as shown below:

Column 9, lines 35 and 42, "tight", each occurrence, should read lightColumn 13, line 22, "gas stream, and the residual cold" should readheavy aromatic oil, whereby said Signed and sealed this 2nd day ofDecember 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, IR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

